Supply device for a combustion chamber

ABSTRACT

A supply device for supplying solid particles and a carrier fluid to a heat generating plant combustion chamber. The supply device has a first end, a second end, a tube, an opening through the tube at the first end, and a supply pipe. A first end of the pipe is proximal to the first end of the supply device and has an opening defining an outlet of the pipe. A second end of the pipe is distal to the first end of the supply device, has an opening defining an inlet of the pipe, and is connected to an inside surface of the tube. The supply pipe defines a curved flow channel within the tube, and the flow channel at the outlet of the pipe has a direction towards the opening through the tube which is at an angle to the longitudinal axis of the supply device.

TECHNICAL FIELD

The invention relates to a method and a supply device for supplying afluid and/or solid particles to a combustion chamber.

BACKGROUND

Generally, heat generating plants, such as boilers, incinerator furnacesand technically corresponding apparatuses are designed to combust orburn different kinds of fuels. Depending on the type of fuel beingcombusted or burnt, different kinds of hazardous gases and/or particlesmay be formed or released. The amount of these hazardous gases and/orparticles depends, among other things, on how well or completely thefuel is being combusted or burnt. This in turn depends on e.g. thetemperature of the grate and the combustion chamber, the amount ofavailable air and other substances that are present to be used by thecombustion process and so on. In order to improve the combustion and inorder to minimise the pollution/emission caused by the hazardous gasesand/or particles, different kinds of supply devices for supplying fluidto an internal combustion chamber of a heat generating plant have beendevised.

Supply devices for supplying fluid to an internal combustion chamber ofa heat generating plant, such as a boiler, an incinerator furnace andtechnically corresponding apparatus are known from SE 9201747-4publication number 502 188 and SE 9304038-4 publication number 502 283both in the same name of ECOMB and their foreign counterparts.

These known fluid supply devices provide comparatively low emissionlevels and great flexibility and enable adjustments to desired emissionlevels to be achieved quickly and reliably. This is attained byarranging a supply device comprising at least one tube to be insertedhorizontally into the combustion chamber.

Said devices also simplify de-sooting and cleaning of the tubes includedin the device, a feature which also enhances the yield of the combustionand vaporisation process respectively.

The devices also enable different fluids or solids to be supplied atdifferent points of time, through one or more of said tubes, so that anew optimal operating point can be set in relation to the prevailingoperating state of the combustion chamber. A particular advantageafforded by the known supply devices is that one or more tubes can bewithdrawn while still enabling the combustion or gasification process tocontinue with the use of the remaining tubes.

Other types of supply devices are described in DE 306 765 (Bauer) andU.S. Pat. No. 5,112,216 (Tenn) for example.

A supply device must be able to operate reliably over a long period oftime in a demanding environment. The tube that is inserted into thecombustion chamber, according to prior art, is subjected to highstresses as a result of the high temperature and the corrosiveenvironment that prevail.

In view of changing conditions within a combustion chamber, the optimalplace for injecting fluid or solid particles into the combustion gasesof the chamber by means of a supply device may vary over time. This hasbeen solved by using a plurality of tubes and/or a plurality ofinjection holes in each tube.

It is a general problem within the field that old heat generating plantsare often designed for fossil fuel combustion, which is less and lessdesirable in view of environmental effects. Many plants are thusconverted for using a renewable or less harmful fuel source such as woodpellets, household waste etc. However, such fuels often have a loverenergy content why a larger amount of fuel may need to be combusted inorder for the plant to operate efficiently. However, the combustionchambers are not so easily modified and it may be very expensive todemolish and rebuild large combustion chambers to allow for a higherfuel supply.

SUMMARY

It is an objective of the present invention to provide an improvedmethod and supply device for injecting/emitting a solid fuel into acombustion chamber.

According to an aspect of the present invention, there is provided atubular supply device for supplying solid particles and a carrier fluidto a combustion chamber in a heat generating plant, said supply devicehaving a first end, a second end and a longitudinal axis and comprising:an outer tube forming an outer lateral surface of the supply device; aninner tube positioned inside the outer tube such that an axial space isformed surrounding the inner tube between said inner tube and the outertube; coolant connectors at the second end of the supply device andconfigured for being inlet and outlet, respectively, of a cooling mediumallowed to circulate in the axial space of the supply device between theinner tube and the outer tube; a connector located at the second end ofthe supply device configured for connecting a supply-line for supply ofthe solid particles into the inner tube; an opening through the outertube and the inner tube at the first end of the supply device; a supplypipe, a first end of the pipe being proximal to the first end of thesupply device and having an opening defining an outlet of the pipe, anda second end of the pipe being distal to the first end of the supplydevice, having an opening defining an inlet of the pipe and beingconnected to an inside surface of the inner tube, the supply pipedefining a curved flow channel within the inner tube wherein the flowchannel at the outlet of the pipe has a direction towards the openingthrough the tubes which is at an angle to the longitudinal axis of thesupply device, the pipe not extending outside of the outer tube.

According to another aspect of the present invention, there is provideda supply device assembly for supplying solid particles and a carrierfluid to a combustion chamber in a heat generating plant, saidcombustion chamber being delimited at least one wall, the assemblycomprising: the tubular supply device of any preceding claim, the supplydevice extending, led by its first end, into the combustion chamberthrough a through hole in the wall of the combustion chamber; adisplacing device in mesh with the supply device for axial displacementof the tube through the hole in the chamber wall; a supply lineconnected to the connector for supply of the solid particles, the supplyline providing a flow channel between the inner tube and a supply sourceof the solid particles.

According to another aspect of the present invention, there is provideda method of supplying solid particles and a carrier fluid to acombustion chamber in a heat generating plant, said combustion chamberbeing delimited at least one wall, the method comprising: providing atubular supply device extending, led by a first end of said supplydevice, into the combustion chamber through a through hole in the wallof the combustion chamber; circulating a cooling medium in an axialspace formed between an inner tube and an outer tube forming an outerlateral surface of the supply device; supplying a flow of solidparticles from a supply source into the inner tube at a second end ofthe supply device; supplying a flow of a carrier fluid into the innertube at the second end of the supply device such that the solidparticles are carried by the carrier fluid in the inner tube from thesecond end of the supply device towards the first end of the supplydevice along a longitudinal axis of said supply device; allowing theflow of carrier fluid carrying the solid particles to enter a supplypipe defining a curved flow channel inside the inner tube, whereby theflow direction is changed; and emitting the flow of carrier fluidcarrying the solid particles from an end outlet of the supply pipe,through an opening through the outer tube and the inner tube at thefirst end of the supply device and into the combustion chamber at anangle to the longitudinal axis of the supply device.

It is an advantage of the present invention that a supply pipe is usedwhich defines a curved flow channel within the tubular supply device.The inlet of the pipe is connected to the inside surface of the innertube, whereby at least a part of the solid particles and carrier fluidflowing within the inner tube is forced into the supply pipe via theinlet. After having entered the supply pipe via the inlet, the flow ofparticles and carrier fluid is guided through the curved flow channel,changing the direction of the flow such that when the flow is injectedinto the combustion chamber through the outlet of the supply pipe, theflow will be at an angle to the longitudinal axis of the tubular supplydevice. Thus, by means of the present invention, the solid particlesflowing through the inner tube can be redirected and emitted into thecombustion chamber in a desired direction to reach a desired locationwithin the combustion chamber.

Further, by the supply pipe not extending outside of the outer tube, thefirst end of the supply pipe is less affected by the harsh (hot andcorrosive) environment in the combustion chamber. Also, the first end ofthe supply pipe does not form a projection extending beyond the tubularform of the supply device, whereby said first end does not interferewith e.g. axial movement of the tubular supply device through a throughhole of a wall of the combustion chamber for inserting or removing thesupply device from the combustion chamber. The ability of redirectingthe flow thus does not interfere with the ability of axial displacementof the supply device.

Generally, all terms used in the claims are to be interpreted accordingto their ordinary meaning in the technical field, unless explicitlydefined otherwise herein. All references to “a/an/the element,apparatus, component, means, step, etc.” are to be interpreted openly asreferring to at least one instance of the element, apparatus, component,means, step, etc., unless explicitly stated otherwise. The steps of anymethod disclosed herein do not have to be performed in the exact orderdisclosed, unless explicitly stated. The use of “first”, “second” etc.for different features/components of the present disclosure are onlyintended to distinguish the features/components from other similarfeatures/components and not to impart any order or hierarchy to thefeatures/components.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is now described, by way of example, with reference to theaccompanying drawings, in which:

FIG. 1 is a schematic side view of an embodiment of a supply device ofthe present invention, when the supply device is inserted into acombustion chamber through a hole in a wall of the combustion chamber(the wall shown in section).

FIG. 2 is a partial schematic side view in longitudinal section of anembodiment of a supply device of the present invention.

FIG. 3 is a partial schematic side view in longitudinal section ofanother embodiment of a supply device of the present invention.

FIG. 4 is a partial schematic side view in longitudinal section ofanother embodiment of a supply device of the present invention.

DETAILED DESCRIPTION

The invention will now be described more fully hereinafter withreference to the accompanying drawings, in which certain embodiments ofthe invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided byway of example so that this disclosure will be thorough and complete,and will fully convey the scope of the invention to those skilled in theart. Like numbers refer to like elements throughout the description.

The term “tube” or “tubular” is intended to denote a hollowsubstantially cylindrical structure being delimited by a lateral surfaceand first and second end surfaces. The lateral surface is substantiallyparallel to the central longitudinal axis of the tube, whereas therespective end surfaces are substantially not parallel to the centrallongitudinal axis of the tube but intersects the central longitudinalaxis of the tube. The tube has a first end with the first end surface,and a second end with the second end surface. Conveniently, the firstand second ends do not include any of the lateral surface. When the tubeis inserted into the combustion chamber, the first end may be regardedas an inner end since it extends, is inserted, into the combustionchamber, whereas the second end may be regarded as an outer end since itextends through an outer wall of the combustion chamber, such that thesecond end is in or outside said outer wall. The apertures discussedherein are thus apertures through one of these surfaces. The second endsurface, i.e. the surface of the second end of the tube, may, dependingon the design of the tube, more or less substantially consist of anaperture. The tube may be a substantially circular tube, i.e. have asubstantially circular cross-section perpendicular to the centrallongitudinal axis, but other shapes are also contemplated, such as asquare or rectangular tube.

That something is at the first or second end of the supply device, suchas the opening thorough the tubes being at the first end of the supplydevice or the displacing device meshing with or engaging the supplydevice at its second end, implies that it is on/in the end surface oron/in the lateral surface but in close proximity of, or adjacent to, theend surface and at least closer to that (first or second) end surfacethan to the other (first or second) end surface of the supply device.

The tubular supply device may be of any size, but it may be convenientto use an outer tube which has a longitudinal length of less than 10 m,such as less than 5 m, in order to reduce the lateral stress on thetube, especially if the supply device is inserted substantiallyhorizontally into the combustion chamber. The diameter of the outer tubemay also be of any size, but it may be convenient to use a tube with adiameter of less than 250 mm, such as less than 200 mm, less than 150mm, less than 120 mm or less than 100 mm, in order to reduce the weightof the supply device to make it more easy to handle and move, axiallyand/or rotationally around its longitudinal axis. Another advantage withusing a smaller supply device is that less cooling may be needed of thetube, since the tube takes up heat in relation to its surface area.

Only one supply device may be used in a combustion chamber, but it mayalso be convenient to use a plurality of supply devices, e.g.substantially parallel to each other, at different positions in thecombustion chamber. The supply devices may then co-operate with eachother to provide optimal supply of the fluid and solid particles in thecombustion chamber, e.g. improved mixture of the fluid and solidparticles with the atmosphere in the combustion chamber and/or improvedcoverage of the combustion chamber volume by being able to supply thefluid and solid particles at more different positions in the combustionchamber.

The supply device may be inserted into the combustion chamber in anydirection. It may be convenient to insert the supply device vertically,e.g. hanging through the top wall (ceiling/roof) of the combustionchamber in order to reduce the lateral stresses on the supply device andthe mounting of the supply device in the chamber wall, and/or on thedisplacing device. On the other hand it may be convenient to insert thesupply device horizontally, e.g. through a side wall of the combustionchamber. Depending on the design on the combustion chamber, it may beeasier to reach the place within the combustion chamber where it isdesired to supply the fluid and solid particles in the combustionchamber with a horizontal supply device. A vertically inserted supplydevice may need to be much longer and heavier in order to reach the sameposition in the combustion chamber as a substantially smallerhorizontally inserted supply device.

The supply device may be provided with means for supplying a coolingagent to said supply device. This has the advantage that the tube canoperate for long periods of time in a very hot environment.

The displacing device or means for displacing said supply device may bearranged so as to permit rotation of the supply device around itslongitudinal axis.

The supply device may further be associated with a cleaning means, e.g.mechanically by means of steel pins or brushes, or pneumatically bymeans of blowing air or steam for cleaning the outer tube during itsaxial inward and/or outward movement in the combustion chamber. As theouter tube is subjected to a combustion process, particles, such as e.g.soot, will eventually be formed on the tube and also at the opening andpipe outlet. The tube will at some point in time need to be withdrawnfrom the combustion chamber to be cleaned. By this arrangement, thesupply device is cleaned swiftly and can be re-inserted immediatelyafter cleaning.

In some embodiments, the opening is through a lateral surface of theinner and outer tubes. In this way the direction of the particle flowmay be conveniently altered to e.g. about 90° in relation to the axialflow within the inner tube. The flow can e.g. be directed downwards,towards the hearth from a horizontally positioned supply device in acombustion chamber. In other embodiments, however, the opening is in theend surface of the first end of the device, e.g. allowing the particlesto be more easily injected forwards along the longitudinal axis wherebythe supply device may extend a shorter length into the combustionchamber, allowing the device to be made smaller and reducing thegravitational strain on a horizontally extending tubular supply device.

In some embodiments, the outlet opening of the pipe has a diameter whichis less than 80%, e.g. less than 50%, of a diameter of the inner tube.This implies that the supply pipe may have a substantially smaller crosssection than the inner tube, allowing the pipe to form the curved flowchannel within the inner tube. The supply pipe may have a substantiallyuniform cross section between its inlet and outlet, although allowingfor some deviations for allowing the pipe to curve. Also, the inner tubemay have a uniform cross section/diameter, at least along the part ofthe inner tube surrounding the supply pipe.

In some embodiments, the outlet opening of the pipe has a diameter whichis less than 80% of the diameter of the opening through the inner andouter tubes. This may allow for a gap to be formed between the supplypipe and the inner and outer tubes at the opening through said tubes.This gap may be advantageous for e.g. allowing access to the inside ofthe inner tube e.g. for maintenance work or for removing or exchangingthe supply pipe. Also or alternatively, the relatively smaller diameterof the supply pipe at its outlet may allow the pipe to be inclined tothe opening through the tubes when extending through said opening (i.e.the pipe does not have to extend at a 90° angle to the longitudinal axiswhen extending through the opening if the opening is through the lateralsurfaces of the tubes.

In some embodiments, the outlet opening of the pipe has a diameter whichis at least 3 cm or at least 5 cm. This relatively large outlet of thesupply pipe allows a relatively large flow rate of the particles andcarrier fluid, allowing a large amount of particles to be injected pertime period. This is advantageous e.g. for efficient injection ofparticles as a primary or secondary fuel into the combustion chamber.Also, the pipe may have a substantially uniform diameter of at least 3cm or at least 5 cm. In some embodiments, the second end of the supplypipe is connected to the inside surface of the inner tube by means of acircumferential flange configured for forcing an axial flow in the innertube, from the second end towards the first end of the supply device,into the pipe. Thus, the pipe may conveniently be fixed to the flangeand the circumferential flange may at the same time prevent the flowfrom passing beside the supply pipe and instead forcing the flow intothe supply pipe. The flange may also comprise guiding parts whichgradually reduces the diameter of the flow channel of the flow in theinner tube before entering the supply pipe. The flange may allow thesupply pipe to be exchangeable. For instance, it may be convenient to beable to replace a supply pipe if it has been corroded or otherwisedamaged, or if a supply pipe having a different curvature or diameter isdesired. If the opening through the tubes is large enough, as discussedabove, the supply pipe may be replaced through said opening without theneed to disassemble the supply device any further.

In some embodiments, the supply pipe comprises a flexible or jointedpart, allowing the angle to the longitudinal axis to be adjusted. Thismay be in addition to or an alternative to switching between differentsupply pipes having different curvatures as mentioned above. Theflexible or jointed part may further improve the ability of adapting towhere in the combustion chamber the particles are injected/emitted bychanging the injection direction. The pipe may be curved by the jointe.g. by hand when the supply device is under maintenance outside thechamber, or by means of mechanical externally operated means while thesupply device is inserted into the chamber (e.g. a motor whichmechanically bends and possibly holds the curvature of the pipe).

In some embodiments, the angle of the flow channel at the outlet of thepipe in relation to the longitudinal axis is between 0 and 90°, such asat least 30°, e.g. between 45° and 90°, e.g. if the opening is through alateral surface of the inner and outer tubes. Thus, the flow directionof the particles is substantially altered in relation to its axial flowthrough the inner tube, by means of the supply pipe.

In some other embodiments, e.g. if the opening is through an end surfaceof the inner and outer tubes, the angle of the flow channel at theoutlet of the supply pipe in relation to the longitudinal axis isbetween 0 and 45°, such as less than 30°. The angle may then be in anydirection, e.g. upwards or downwards from a longitudinal direction of ahorizontally mounted supply device.

Regardless of whether the opening is through a lateral or end surface,the angle may be towards a direction against the flow direction of thegas in the combustion chamber, typically downward for a horizontallymounted supply device.

In some embodiments, the supply device is mounted through a through holein a wall of the combustion chamber, e.g. a vertical wall if the deviceis inserted horizontally into the chamber, or a horizontal wall if thedevice is inserted vertically into the chamber e.g. hanging from theceiling. In some embodiments, a displacing device is in mesh with thesupply device for axial displacement of the tubular device through thehole in the chamber wall. By axial displacement, the position in thechamber to where the particles are injected/emitted (the terms injectedand emitted are herein used interchangeably) may be controlled, and thetubular device may be removed to the outside of the chamber formaintenance etc. In some embodiments, the supply device may be axiallydisplaced out from the combustion chamber when it is not in use, i.e.when it is not supplying solid particles into the combustion chamber.Additionally, the displacing device may be arranged for rotation of thetubular supply device, further increasing the control of to where theparticles are injected.

In some embodiments, the supply device is associated with a particleanalysing device arranged for measuring a particle size of the solidparticles in a flow channel between the supply source and the pipeoutlet. The particle size may e.g. be a number average particle size ora weight average particle size. The size of the particles may berelevant for to where in the chamber they should be injected, which maybe controlled by different controlling parameters e.g. by the curvatureof the supply pipe, the speed/pressure of the carrier fluid and/or theposition (axial displacement and/or rotation) of the supply device inthe chamber. E.g. a particulate fuel having a large particle size maytravel further from the supply device before combusting than a fuelhaving a smaller particle size. Associating the particle analysingdevice may e.g. allow any of the controlling parameters to be adjustedin view of continuous or periodic analysis of the particle size. This isrelevant e.g. since the particle size can vary over time. For instance,larger particles have a tendency to move to the top of a supply source.In some embodiments, the supply device is associated with a control unitconfigured for controlling the angle between the direction of the pipeoutlet and the longitudinal axis depending on the particle size measuredby the particle analysing device. In some embodiments, the supply deviceis associated with a carrier fluid compression unit configured to adjustthe pressure of the carrier fluid depending on the particle sizemeasured by the particle analysing device.

In some embodiments, a flame detector is mounted on the supply deviceinside the combustion chamber. The flame detector may e.g. be connectedto the control unit and/or compression unit for regulating the particleemission in view of flame detection.

In some embodiments, the heated cooling medium exiting the supply deviceis used to pre-heat the carrier fluid before it enters the supplydevice, e.g. by means of a liquid-gas heat exchanger if the coolingmedium is a liquid and the carrier fluid is a gas. Thus, energy which islost from the combustion chamber due to the cooling of the supply devicemay be restored to the chamber by the carrier fluid.

In some embodiments, the solid particles are of a fuel for thecombustion chamber. The particles may be a primary fuel, but it may beconvenient to use the supply device of the present invention for addinga secondary fuel, complementing a primary fuel added at the bottom grateof the chamber. When the particles are a secondary fuel, the particlesmay be supplied counter current to the combustion gases from theupstream main combustion zone. The supply device may be used whenadditional (secondary) fuel is useful for obtaining extra power/effectfrom the furnace, e.g. less than 50% additional power/fuel such asbetween 10 and 30% may be added by means of the supply device. Thepresent invention may be used for upgrading a heat generating plantwhich is designed for fossil fuel combustion. If a more environmentallyfriendly primary fuel is used, such as wood pellets or household waste,the grate and combustion chamber may not be designed for the lowerenergy density of such a fuel, why the heat generating plant may notoperate optimally. In such a case, the combustion chamber may easily beupgraded by making a through hole in one of its walls for insertion ofthe supply device of the present invention for supplying a particulatesecondary fuel to the combustion chamber for combustion in thecombustion gases from the primary fuel. This is a much simpler andcheaper upgrade than a more extensive upgrade for allowing more primaryfuel to be combusted. The solid particles may e.g. be of a mediumcalorific fuel such as a non-fossil fuel e.g. a wood powder, or of ahigh calorific fuel such as a fossil fuel e.g. a plastics powder, or ofa low calorific fuel such as sewage sludge, or of a mixture thereof.

Thus, in some embodiments, a primary fuel is combusted at the bottom ofthe combustion chamber and the solid particles are a secondary fuelemitted into combustion gases of the combustion chamber from thecombustion of the primary fuel. In some embodiments, the solid particlesare emitted in a direction which is at least partly counter current tothe combustion gases. This may improve the combustion of the fuelparticles.

In some embodiments, at least 100 kg/h, e.g. at least 500 kg/h or atleast 1000 kg/h, of solid particles are emitted from the supply pipe.

This implies that a large amount of e.g. secondary fuel can be injectedinto the combustion chamber.

In some embodiments, the carrier fluid is air, recirculated flue gas,oxygen enriched air, oxygen, or a mixture thereof. If the carrier fluidcomprises oxygen, the present device may additionally be designed toprovide secondary oxygen to the combustion chamber for improvedcombustion.

FIG. 1 is a schematic illustration of an embodiment of a supply device 1of the present invention, when the supply device is inserted into acombustion chamber 4 through a hole 23 in a wall 24 of the combustionchamber. The supply device 1 has a first end 5 extending into thecombustion chamber 4 and a second end 6 extending out of said chamber 4.The supply device 1 has a longitudinal axis 7 which is herein used forreference when discussing the present invention. The wall 24 may e.g. bea vertical or a horizontal wall of the combustion chamber 4. Coolantconnectors 10 at the second end 6 of the device 1 provides an inlet andan outlet of cooling medium circulating in the supply device. A coolantsupply pipe 25 guides cooling medium, e.g. water, from a coolant source27, and a coolant recirculation pipe 26 guides the heated coolant fromthe supply device, e.g. back to the coolant source 27 to be cooled,possibly partly by heat exchanging with the carrier fluid before saidfluid enters the supply device. A connector 11 for connecting asupply-line 12 for supply of the solid particles into the supply devicefrom a particle supply source 28 is also positioned at the second end 6of the device 1. The particles may be transported through the supplyline 12 by and in mixture with the carrier fluid, or the particles maybe mixed with the carrier fluid at a later stage inside the supplydevice. An opening 13 through a later surface of the tubular supplydevice allows an outlet opening 17 of the supply pipe to emit theparticles and carrier fluid into the chamber 4, e.g. at least partlycounter currently with the combustion gases in the combustion chamber.

FIG. 2 is a schematic illustration in longitudinal section of the firstend 5 of an embodiment of the supply device 1. An outer tube 8 forms anouter lateral surface of the supply device and an inner tube 9 ispositioned inside the outer tube such that an axial space 14 is formedsurrounding the inner tube 9 between said inner tube and the outer tube8. The axial space 14 is configured for allowing a cooling medium toflow there through. There is an opening 13 through the outer tube 8 andthe inner tube 9 at the first end 5 of the supply device 1. A supplypipe 15 is positioned inside the inner tube 9. A first end 16 of thepipe 15 is proximal to the first end 5 of the supply device and has anopening 17 defining an outlet of the pipe 15, and a second end 18 of thepipe is distal to the first end 5 of the supply device. The second end18 has an opening 19 defining an inlet of the pipe 15 and beingconnected to an inside surface of the inner tube 9. The supply pipe 15defines a curved flow channel 20 within the inner tube 9 wherein theflow channel at the outlet 17 of the pipe 15 has a direction towards theopening 13 through the tubes 8 and 9 which is at an angle α to thelongitudinal axis 7 of the supply device. In the embodiment of FIG. 2,the angle α is about 90° to emit the particles 2 in a directionperpendicular to the longitudinal axis 7 as indicated by the bold arrowat the outlet opening 17. The pipe 15 does not extend outside of theouter tube 8, but ends substantially in level with the outer tube 8. Inthe embodiment of FIG. 2, a particle supply pipe 22 extends inside andalong the inner tube 9 for transporting the particles, possibly by meansof and mixed with a part of the carrier fluid 3 within the supplydevice. The particles are then injected into the inner tube from theparticle supply pipe (as indicated by the bold arrow) and mixed with thecarrier fluid 3 flowing (as indicated by the broad arrows) beside theparticle supply pipe 22 in the inner tube before the mixture enters thesupply pipe 15 via its inlet 19. At its second end 18, the supply pipe15 is fixed to the inner tube 9 by a circumferential flange 21.

FIG. 3 is a schematic illustration in longitudinal section of the firstend 5 of another embodiment of the supply device 1. An outer tube 8forms an outer lateral surface of the supply device and an inner tube 9is positioned inside the outer tube such that an axial space 14 isformed surrounding the inner tube 9 between said inner tube and theouter tube 8. The axial space 14 is configured for allowing a coolingmedium to flow there through. There is an opening 13 through the outertube 8 and the inner tube 9 at the first end 5 of the supply device 1. Asupply pipe 15 is positioned inside the inner tube 9. A first end 16 ofthe pipe 15 is proximal to the first end 5 of the supply device and hasan opening 17 defining an outlet of the pipe 15, and a second end 18 ofthe pipe is distal to the first end 5 of the supply device. The secondend 18 has an opening 19 defining an inlet of the pipe 15 and beingconnected to an inside surface of the inner tube 9. The supply pipe 15defines a curved flow channel 20 within the inner tube 9 wherein theflow channel at the outlet 17 of the pipe 15 has a direction towards theopening 13 through the tubes 8 and 9 which is at an angle α to thelongitudinal axis 7 of the supply device. In the embodiment of FIG. 3,the angle α is about 45° to emit the particles 2 in a direction which isnot perpendicular to the longitudinal axis 7, as indicated by the boldarrow at the outlet opening 17. The pipe 15 does not extend outside ofthe outer tube 8, but ends substantially in level with the outer tube 8.In the embodiment of FIG. 3, a particle supply pipe 22 is not used.Rather, the particles 2 and carrier fluid 3 are mixed with each otherupon entering the inner tube via the connector 11. At its second end 18,the supply pipe 15 is fixed to the inner tube 9 by a circumferentialflange 21 including guides for guiding the flow of particles and carrierfluid into the pipe 15.

FIG. 4 is a schematic illustration in longitudinal section of the firstend 5 of another embodiment of the supply device 1. An outer tube 8forms an outer lateral surface of the supply device and an inner tube 9is positioned inside the outer tube such that an axial space 14 isformed surrounding the inner tube 9 between said inner tube and theouter tube 8. The axial space 14 is configured for allowing a coolingmedium to flow there through. There is an opening 13 through the endwall of the outer tube 8 and the inner tube 9 at the first end 5 of thesupply device 1. A supply pipe 15 is positioned inside the inner tube 9.A first end 16 of the pipe 15 is proximal to the first end 5 of thesupply device and has an opening 17 defining an outlet of the pipe 15,and a second end 18 of the pipe is distal to the first end 5 of thesupply device. The second end 18 has an opening 19 defining an inlet ofthe pipe 15 and being connected to an inside surface of the inner tube9. The supply pipe 15 defines a curved flow channel 20 within the innertube 9 wherein the flow channel at the outlet 17 of the pipe 15 has adirection towards the opening 13 through the tubes 8 and 9 which is atan angle α to the longitudinal axis 7 of the supply device. In theembodiment of FIG. 4, the angle α is about 30° to emit the particles 2in a direction which is not perpendicular to the longitudinal axis 7, asindicated by the bold arrow at the outlet opening 17. The opening 13 isthrough an end wall of the inner and outer tubes, as opposed to througha lateral wall as in the embodiments of FIGS. 1, 2 and 3. The pipe 15does not extend outside of the outer tube 8, but ends substantially inlevel with the outer tube 8. In the embodiment of FIG. 4, a particlesupply pipe 22 is not used. Rather, the particles 2 and carrier fluid 3are mixed with each other upon entering the inner tube via the connector11. At its second end 18, the supply pipe 15 is fixed to the inner tube9 by a circumferential flange 21 including guides for guiding the flowof particles and carrier fluid into the pipe 15.

According to another embodiment of the present invention, there isprovided a tubular supply device (1) for supplying solid particles (2)and a carrier fluid (3) to a combustion chamber in a heat generatingplant, said supply device having a first end (5), a second end and alongitudinal axis and comprising: a tube (8, 9); an opening (13) throughthe tube at the first end; and a supply pipe (15), a first end (16) ofthe pipe being proximal to the first end of the supply device and havingan opening (17) defining an outlet of the pipe, and a second end (18) ofthe pipe being distal to the first end of the supply device, having anopening (19) defining an inlet of the pipe and being connected to aninside surface of the tube, the supply pipe defining a curved flowchannel (20) within the tube wherein the flow channel at the outlet ofthe pipe has a direction towards the opening through the tube which isat an angle (α) to the longitudinal axis of the supply device. In someembodiments, the tube comprises an outer tube (8) forming an outerlateral surface of the supply device; and an inner tube (9) positionedinside the outer tube such that an axial space (14) is formedsurrounding the inner tube (9) between said inner tube and the outertube (8). In some embodiments, the supply device (1) further comprisescoolant connectors (10) at the second end (6) of the supply device andconfigured for being inlet and outlet, respectively, of a cooling mediumallowed to circulate in the axial space (14) of the supply devicebetween the inner tube (9) and the outer tube (8). In some embodiments,the supply device (1) further comprises a connector (11) located at thesecond end (6) of the supply device configured for connecting asupply-line (12) for supply of the solid particles (2) into the innertube (9). In some embodiments, the supply pipe (15) does not extendoutside of the outer surface of the tube (8).

The invention has mainly been described above with reference to a fewembodiments. However, as is readily appreciated by a person skilled inthe art, other embodiments than the ones disclosed above are equallypossible within the scope of the invention, as defined by the appendedpatent claims.

1-21. (canceled)
 22. A tubular supply device for supplying solidparticles and a carrier fluid to a combustion chamber in a heatgenerating plant, the supply device having a first end, a second end anda longitudinal axis and comprising: an outer tube forming an outerlateral surface of the supply device; an inner tube positioned insidethe outer tube such that an axial space is formed surrounding the innertube between the inner tube and the outer tube; coolant connectors atthe second end of the supply device and configured as an inlet and anoutlet, respectively, for a cooling medium allowed to circulate in theaxial space of the supply device between the inner tube and the outertube; a connector located at the second end of the supply deviceconfigured for connecting a supply-line for supply of the solidparticles into the inner tube; an opening through the outer tube and theinner tube at the first end of the supply device; and a supply pipe, afirst end of the supply pipe being proximal to the first end of thesupply device and having an opening defining an outlet of the supplypipe, and a second end of the supply pipe being distal to the first endof the supply device, having an opening defining an inlet of the supplypipe and being connected to an inside surface of the inner tube, thesupply pipe defining a curved flow channel within the inner tube whereinthe flow channel at the outlet of the supply pipe has a directiontowards the opening through the outer tube and the inner tube which isat an angle to the longitudinal axis of the supply device, the supplypipe not extending outside of the outer tube.
 23. The supply device ofclaim 22, wherein the opening is through a lateral surface of the innertube and the outer tube.
 24. The supply device of claim 22, wherein theoutlet opening of the supply pipe has a diameter which is less than 80%of a diameter of the inner tube.
 25. The supply device of claim 22,wherein the outlet opening of the supply pipe has a diameter which isless than 80% of the diameter of the opening through the inner tube andthe outer tube.
 26. The supply device of claim 22, wherein the outletopening of the supply pipe has a diameter which is at least 3 cm. 27.The supply device of claim 22, wherein the second end of the supply pipeis connected to the inside surface of the inner tube by means of acircumferential flange configured for forcing an axial flow in the innertube, from the second end towards the first end of the supply device,into the supply pipe.
 28. The supply device of claim 22, wherein thesupply pipe comprises a flexible part, allowing the angle to thelongitudinal axis to be adjusted.
 29. The supply device of claim 22,wherein the angle of the flow channel at the outlet of the supply pipein relation to the longitudinal axis is at least 30°.
 30. A supplydevice assembly for supplying solid particles and a carrier fluid to acombustion chamber in a heat generating plant, the combustion chamberbeing delimited by at least one wall, the assembly comprising: thetubular supply device of claim 22, the supply device extending, led byits first end, into the combustion chamber through a through hole in thewall of the combustion chamber; a displacing device in mesh with thesupply device for axial displacement of the tubular device through thehole in the chamber wall; and a supply line connected to the connectorfor supply of the solid particles, the supply line providing a flowchannel between the inner tube and a supply source of the solidparticles.
 31. The assembly of claim 30, further comprising a particleanalysing device arranged for measuring a particle size of the solidparticles in a flow channel between the supply source and the supplypipe outlet.
 32. The assembly of claim 31, further comprising a controlunit configured for controlling the angle between the direction of thesupply pipe outlet and the longitudinal axis depending on the particlesize measured by the particle analysing device.
 33. The assembly ofclaim 31, further comprising a carrier fluid compression unit configuredto adjust the pressure of the carrier fluid depending on the particlesize measured by the particle analysing device.
 34. A method ofsupplying solid particles and a carrier fluid to a combustion chamber ina heat generating plant, the combustion chamber being delimited by atleast one wall, the method comprising: providing a tubular supply deviceextending, led by a first end of the supply device, into the combustionchamber through a through hole in the wall of the combustion chamber;circulating a cooling medium in an axial space formed between an innertube and an outer tube forming an outer lateral surface of the supplydevice; supplying a flow of solid particles from a supply source intothe inner tube at a second end of the supply device; supplying a flow ofa carrier fluid into the inner tube at the second end of the supplydevice such that the solid particles are carried by the carrier fluid inthe inner tube from the second end of the supply device towards thefirst end of the supply device along a longitudinal axis of the supplydevice; allowing the flow of carrier fluid carrying the solid particlesto enter a supply pipe defining a curved flow channel inside the innertube, whereby the flow direction is changed; and emitting the flow ofcarrier fluid carrying the solid particles from an end outlet of thesupply pipe, through an opening through the outer tube and the innertube at the first end of the supply device and into the combustionchamber at an angle to the longitudinal axis of the supply device. 35.The method of claim 34, wherein the solid particles are a fuel.
 36. Themethod of claim 34, wherein at least 100 kg/h of solid particles areemitted from the supply pipe.
 37. The method of claim 34, wherein aprimary fuel is combusted at the bottom of the combustion chamber andthe solid particles are a secondary fuel emitted into combustion gasesof the combustion chamber from the combustion of the primary fuel. 38.The method of claim 37, wherein the solid particles are emitted in adirection which is at least partly counter current to the combustiongases.
 39. The method of claim 34, further comprising: measuring aparticle size of the solid particles in a flow channel between thesupply source and the supply pipe outlet; and adjusting the angle atwhich the flow is emitted by changing the curved flow channel of thesupply pipe based on the measured particle size.
 40. The method of claim34, further comprising: measuring a particle size of the solid particlesin a flow channel between the supply source and the supply pipe outlet;and adjusting the pressure, and thus velocity, of the carrier fluidbased on the measured particle size.